Control lever



Oct. 30, 1945. M B RHODES 2,388,079

GONTRL LEVER Filed Sept. 21, 1944Y 3 Sheets-Sheetl x7 f? CRU/.s/N .5;21, M/xrz/RE o raf/L mc# 50 M/XTURE /0E CUTOFF' 35% JMJ/hd, l www Qct. 3o, 1945. M B. RHom-:s 'A 2,388,079

CONTROL LEVER Patented Oct. 3 0,` 1945 CONTROL LEVER Murray B. Rhodes, Kew Gardens, N. Y., assignor to The Glenn L. Martin' Company, Middle River, Md., a corporation of Maryland Application september 21, 1944.,l seriall No. 555,071 5. claims. (o1. vll- 471)` This invention relates to an engine control device, and more particularly to a lever control for the fuel systems of aircraft engines.

An object of the invention is to provide a throttle operating' mechanism combined with a mixture. control lever for aircraft engines with the two levers so coordinated that it is impossible for the pilot to close the throttle without adjusting the mixture lever to its full rich position. The inventioniembraces a connecting means for the two levers so that when the throttle is moved to its closed position from its open or cruising position the mixture lever is also moved from its cruising lean position to its full rich position and thereby prevents the engine from stalling if the throttle lever is suddenly moved to its open or cruising position. This movement of the throttle lever does not affect the position of the mixture lever. When it is desirable to set the mixture lever to the cruising lean position, it is done by an intentional eiort on the part of the pilot Without affecting the position of the throttle lever.

The present invention is an improvement over my prior Patent No. 2,292,091, patented August 4, 1942, and is designed to accommodate mixture levers moving opposite to the throttle levers. In the instant case the throttle lever is connected to the mixture lever by a one-way clutch mechanism and does not use the detachable hooking means for the levers shown in my prior patent. In normal operation when the pilot starts his engine he must chokeY or provide a rich mixture l for his engine and to accomplish this the mixture lever is moved to the desired point to adjust the carburetor to` pass a rich mixture to the engine and the throttle lever is opened partially. As the engine` warms up the mixture lever can be readily adjusted to prevent overchoking of the engineregardless of the position of the throttle lever. A fter the plane has taken oil' and leveled out for cruising the mixture lever is manually adjusted to its cruising lean position, or in other words, to a position near the idle cut-off position. Ifit becomes necessary for the pilot to retard the throttle, the mixture lever is progressively moved from its lean to its full richI position which is reached as the throttle approaches its closed position. In use. the mixture lever is only adjusted' under certain conditions of starting and idling the engine while on the other hand the throttle is manipulated for various operations 0f the plane. The great danger confronting the pilot is the unintentional cutting down of the speed of the engine without readjusting the mixture control which results in stalling the engi-ne. military aircraft under battle conditions.

In the drawings:

Fig. 1 isa rear view of the engine throttle and mixture control lever assembly;

Fig. 2` is a front view of the apparatuswith the lever positioned'as in'Fig. 1; and

Fig. 3 is a horizontal sectional view taken on line 3--3 of Fig. 1` and showing the selective connecting means between the two levers.

Essentially the presentV engine fuel control apparatus consists` of a throttle lever I and a mixture lever 3'mounted to turn abouta common axis 5 within the frame 1, the levers I and 3 being carried` between arcuate end members 0 and Il, respectively, and the central frame 1 whereby when the levers are moved they adjust the fuel system of the engine through suitable mecha-` nism, not disclosed; As shown, the throttle lever I and mixture lever Sareadapted forindivid-ual manual adjustment, the throttle lever being movable throughout the length of the arcuate end segments 9. and' I'I, or about 60, while the mixture lever is adjustable over a range of about 351/2" from its cut-off toits full rich position, these segments being secured to the ends of central frame 1 by suitable means I3. Preferably, non-metallic separators llil are used to-frictionally hold the. levers I- and 3 in adjusted position.

On the lower portion of the throttle lever I an arcuate toothed rack I1 is mounted having teeth I9 thereon normally meshing with the toothed. gearV 2I as will be hereinafter described.

The mixture lever 3 adjacent the opposite end of the central. frame member 1 is provided withV a segmental rack 23 having teeth 25 thereon carried on an inwardly extending arm 21 secured to the lower portion of the lever. This toothed segmentZ` normally meshes with a gear l2&1 mounted on bushing 3l and carried'on horizontal shaft 33 theends `of theY shaft being carried in depending arms. 35and 31 of the central frame 1 and. secured in position by cotter pins or` the like. The depending arm, 35 of the central frame Y This. is especially truein 4| are outwardly projected by spring arms 45 of toothed gear 2| and the bell-shaped clutch collar integrally attached to the hub of gear 29. These several parts are normally maintained in cooperating relation by compression spring 53 carried on'shaft `33 and bearing `against the face of gear 29 and the lower portion 'of depending arm 35.

Thus, when the parts are in the position shown in Fig. 2-, that is in normal flight, with the throttle lever l open and the mixture lever at cruising lean and the pilot moves the throttle toward closed position the mixture lever 3 is automatically connected to the throttle lever and moves to full rich`position. This is accom- .plished by rack I9 meshing with the teeth'on gear 2| which is rotated and the movement transmitted to the bell-shaped clutch collar 5| through engagement of the pivoted dogs 4I with the teeth 41 formed in the llange collar to transmit rotary movement to the connected gear 29. The teeth thereon meshing with rack 25 carried by arm 21 and aiixed to the mixture control moves the mixture lever 3 backward to full rich position so that it is impossible to stall the engine by reducing the fuel thereto without increasing the rich-v ness of the mixture. Although there is some lost motion between the parts, it will be noted that due to the use of 4 dogs 4| cooperating with an equal number of rack teeth 41, movement of the throttle I can only move a comparatively short distance before a positive clutching occurs and the mixture lever 3 is connected therewith and is carried rearwardly to "full rich. `The throttle I generally works through an angle of 60 from open to closed position while the mixture control 3 moves through an angle of 30 from its `normal cruising lean position (when the throttle is open) to its "full rich position (when the throttle is closed).

When rst starting up it is necessary to permit the mixture lever to have independent movement aside from its tie-in movement with the throttle and this is accomplished by disengaging the clutch collar 5| from engagement with dogs 4|. As shown in dotted lines in Fig. 3, when the handle 55 pivoted on studl 51 of the mixture lever 3 is grasped together with the ball 59 on the mixture lever the link arm* 6I is elevated and in turn raises arm 63 attached to crank 65 pivoted at 61 to stud 69 and moves horizontal rod 1| passing through opening attached to the lever arm of crank `65 with the lower surface of hook rod 1| suitably supported on a bottom roller 11. The upturned portion 13 of hook rod 1| engages the outer face of gear 29 and disengages it from rack 25 and also moves the clutch colla1w5l from engagement with the dogs 4I as shown in dotted llines in this view. Thus the mixture may vintentionally move from its closed position to "full rich or to any desired intermediate point when the pilot presses the printed handle 55 but when the gear train described-is in lmeshing engagement the pilot has only the throttle lever to operate and ber assured that he will not stall his 1. In an engine control mechanism, .a throttle lever movable between closed and open positions, a mixture control member movable between lean and rich positions and means actuated by the -throttle lever comprising a rack adapted to engage a one-way clutch, a pinion mounted c0- axial with said one-way clutch to rotate therewith, said pinion meshing with a second rack mounted on Vsaidmixture control member so that movement of the throttle from open to closed position rotates said pinion meshing with said second rack to move said control mixture toward its rich position, and manual means secured to the mixture control member for disengaging said pinion and one-way clutch from the said racks.

2. In an engine control mechanism, a throttle lever and a mixture lever mounted to swing about an axis, racks secured to each of said levers and meshing with gears mounted lon a common axle, a clutch interposed between said gears and manual operable means on the said mixturelever for disengaging the said clutch whereby the mixture lever may be operated independently of the throttle lever.

3. In an engine control mechanism the combination of a pair of levers mounted to swing about an axis, a clutch, an arcuate rack mounted on each lever, toothed gears connected through said clutch and axially supportedV on arcommon axle and adapted to be rotated Yby one of said racks, and manually operated means pivoted to one of said levers for shifting a portion of said clutch and one of said toothed gears along said axle andout of operable engagement with the other of said toothed gears.

4. In an engine control mechanism, a throttle y lever and a mixture lever mounted in an arcuate frame' and adapted to swing about an axis, toothed racks carried by said levers and meshing with pinions mounted on a horizontal axle, one of said gears having-an enlarged flange collar integrally secured to the hub portion thereof, teeth positioned within the enlarged llange collar, spring biased dogs mounted on the face of the other of said gears normally meshing with the teeth in the said enlarged collar and means for sliding the'rslJ mentioned gear and its assocated flange collar on the said horizontalaxle engine when he moves the throttle from open to closed position, or from closed to open position.

I claim: .l

out of engagement with the rack on the mixture lever and the spring' biased dogs on the other of said gears, respectively.

5. In an engine control mechanism, an Varcuate frame including a central portion and end plates secured thereto, a throttle lever and a mixture lever mounted between the central frame and the'said end plates, spaced depending Yarms carried on the central frame portion, anY axle mounted in said depending arms, gears'carried on the said axle meshing with toothed racks carried on the throttle and 'mixture levers,'a oneway clutch mounted for turning about said axle interposed between said gears, the elements of said clutch being carried by saidg'ears and a piv- MURRAY B. RHODES. 

